1. Field of the Invention
This invention relates to locking devices for threaded fasteners, and more particularly to a lock washer having reversible oppositely disposed locking surfaces.
2. Description of the Prior Art
Various problems and difficulties have been and are being encountered with the known lock washers which have a cam-locking surface and an oppositely disposed engaging surface, such as a plurality of radial teeth. Lock washers of this type are generally formed having one surface consisting of a plurality of contiguous cam members, and the opposite surface having a plurality of radially arranged tooth members.
Generally, this type of washer must be used in pairs to provide a working arrangement. Each washer must then be positioned so that the cam surfaces are in opposing engagement with each other, and the toothed surfaces are facing outwardly, so that one toothed surface is positioned to engage the head of a bolt or the nut thereof, and the other toothed surface is positioned to engage the workpiece. This type of washer is disclosed in U.S. Pat. Nos. 3,263,727 and 4,134,438.
Further, a single lock washer of this type is employed wherein the undersurface of a screw head or one surface of the nut includes engaging cam members. Thus, the cam surface of the lock washer will readily engage the opposing cam surface of the head or nut.
However, during assembly of these types of fasteners and lock washers, error in correctly positioning the lock washer becomes a critical problem. The opposing cam surfaces must be positioned correctly for locking engagement; and thus, if a lock washer is inadvertently mispositioned relative to the associated cam surface of another washer or cam nut, a crucial situation between the fastener and its associated workpiece is established, by allowing the fastener to readily loosen and separate from the workpiece.
Hence, with the known-lock washer devices, extreme care must be taken at all times when using them in the assembly of parts or workpieces.